Working memory refers to the cognitive capacity that enables the temporary on-line maintenance and manipulation of information when that information is no longer present in the environment. An increasingly important goal for contemporary cognitive neuroscience is to determine which of the many component processes that can contribute to working memory performance are supported by PFC, and which are supported by other brain systems. The component processes that are the focus of this proposal are storage and the subset of control processes that directly facilitate storage. The theoretical framework informing all of the experiments described here is a distributed processes view that holds that most working memory functions are not supported by specialized memory systems, but rather that they arise through the coordinated recruitment, via attention, of brain systems that have evolved to accomplish sensory, representational, or action-related functions. The specific aims of this project are: 1. To test the hypothesis that working memory storage functions are supported in a domain-specific manner in posterior cortical areas, not in PFC. 2. To test the hypothesis that PFC-mediated control processes can protect the contents of working memory storage from interference. Interference can come from two sources, external and internal. a. Hypothesis addressing external interference: An attentional filtering mechanism supported by dorsolateral PFC controls interference from competing stimuli in the environment. b. Hypothesis addressing internal interference: An inhibitory control mechanism supported by left inferior PFC mediates the effects of proactive interference.